1 Introduction

= cl-package-locks overview =
This library aims to provide a uniform way of dealing with
package-locks across those common lisp implementations that
provide them. If a given implementation does not provide a
package-lock mechanism then no action will be taken by the
use of this library.
= Motivation =
In loading LISA I noticed a package lock violation during
compilation. I was interested in correcting the violation
since I assume it's the reason the package isn't included
in quicklisp, etc.
I found the package lock violation was due to a class reader
function being named CLASS-NAME, which would add a method to
the package-lock protected CLASS-NAME generic-function.
I thought about modifing the name of the function, but then
realized that the LISA has been around a while and how altering
the name might cause compatability issues (however small).
So I decided I'd hack in some code to disable the package-lock
and after dealing with sbcl, cmucl, AllegroCL.. I realized this
might be better suited for a general purpose library, so I
created this small lib to accomplish the task.
In doing some early research to see if others had delt with this
issue I discovered this thread:
http://coding.derkeiler.com/Archive/Lisp/comp.lang.lisp/2009-02/msg01372.html
This library distinguishes itself from the above by not trying
to eleminiate redefinition warnings or use the native
without-package-locks macro's provided by most package-locking
implementations. It also provides some general use functions
and macros that might be useful in dealing with package locking.
I find this library to satisfy my needs with loading LISA and I
hope it suits others in their moments of package-lock violation
need :)
= Status =
Barely coded and tested using sbcl. Needs more testing on
AllegroCL, clisp, and cmucl. I'm also interested in creating
a uniform way of dealing with package-lock errors and providing
implementation agnostic restarts. Another important piece is
looking at how the various implementations implement
without-package-locks to see if I'm missing anything important .
= A Brief HowTo =
(in-package :cl-package-locks)
; Testing if packages are locked
(package-locked-p :cl-user)
; Locking a package
(lock-package (find-package :cl-user))
; Unlocking a package, notice that packages can be described
; in several different ways (currently symbol & package).
(unlock-package 'cl-user)
; Working on lists of packages. The RESOLVE-PACKAGES function
; converts a list of package descriptors to packages or errors.
(let ((pkgs (resolve-packages '(:cl-package-locks :swank))))
(lock-packages pkgs)
; your code here
(unlock-packages))
; Temporarily unlocking a list of packages
(with-packages-unlocked (cl mop)
; something dangerous
t)
; Temporarily unlock all packages
(without-package-locks
; something dangerous
nil)
; List all unlocked packages
(all-unlocked-packages)
; List all locked packages
(all-locked-packages)